1. Field of the Invention
The present invention relates to thrombectomy devices, and more particularly to manual thrombectomy devices for inexpensively and easily detaching, macerating and removing thrombi organized in not only native vessels, but also graft prostheses such as arterio-venous grafts (AVG) or other vessel grafts.
2. Description of the Related Art
Not only in native vessels of a human body, but also in graft prostheses such as arterio-venous grafts or other vessel grafts used in a blood dialyses operation and the like, blood is changed into clotted masses as thrombi which are stacked or organized stubbornly to adhere to the vessel wall for interrupting blood flow and for consequently blocking the blood vessel. Therefore, various medicines and devices to remove the thrombi have been developed.
The conventional methods for removing the thrombi are largely classified into a chemical method using thrombolytic agents to dissolve clots and a physical method using devices inserting into a blood vessel such as a catheter.
The representative thrombectomy devices having developed until now are described below.
First, a commercialized AngioJet, a rheolytic thrombectomy catheter, which removes the thrombi by water jet flowed out through an outflow orifice equipped at a distal end portion of the catheter, is known.
Korean Patent No. 10-1303612 discloses a technique using a thrombus retrieving stent module equipped with a stent having a mesh member at a distal end of a push wire inserted in a micro-tube for catching and retrieving the thrombi into the inside of an expanded catheter.
U.S. Pat. No. 6,458,145 discloses a technique using three loops connected together and equipped at a distal end of a lumen shaft for catching and removing the thrombi (the loop-type similar patents are disclosed in U.S. Pat. No. 6,099,534, No. 3,828,790, etc.).
U.S. Pat. No. 5,766,191 discloses a technique using a filament cage connected by a hub at a distal end of a lumen shaft for catching and retrieving the thrombi into the inside of the lumen shaft (the cage-type similar patents are disclosed in U.S. Pat. No. 8,475,487, Korean Patent No. 10-1332616, etc.).
U.S. Pat. No. 8,361,095 discloses a technique using a thrombus engagement members disposed helically at a torsion member connected to a torque shaft located inside an inner sheath for engaging and retrieving the thrombi into the inner sheath.
The rheolytic thrombectomy catheter generally reduces the thrombectomic ability in a vessel having a large inner diameter and has the inability to remove organized and wall-adherent thrombi.
In case of the mesh or loop used to catch the thrombi and retrieve into the inside of the catheter such as Korean Patent No. 10-1303612 and U.S. Pat. No. 6,458,145, the complete removal and retrieval of the thrombi is difficult. U.S. Pat. No. 5,766,191 is the cage-type, but has similar problems as the loop-type.
In U.S. Pat. No. 8,475,487, the distal and proximal ends of a plurality of filaments are attached to each of cylindrical rings, respectively. When the plurality of filaments is expanded to form a cage, the distal end ring is proximally slid on the catheter tube because it is not fixed to the catheter tube. However, when the catheter tube is rotated to remove the thrombi, the torque is only transmitted to the expanded cage through the proximal end ring fixed to the catheter tube. Therefore, the thrombi are inefficiently removed. U.S. Pat. No. 8,475,487 has a function of the rheolytic thrombectomy catheter because a high pressure tube and a fluid jet emanator are coupled at the inside of the catheter tube. However, the high pressure tube and the fluid jet emanator have to be especially installed. Because the high pressured fluid of the fluid jet emanator is indirectly jetted through outflow orifices by proximally jetting in the inside of the catheter instead of directly jetting to the thrombi in the wall, the thrombus removing efficiency of the pressured fluid is reduced and the detached thrombi are not efficiently retrieved by inflow orifices.
Korean Patent No. 10-1332616 has cage-shaped fragmentation wires having one end connected to a control ball moving proximally and distally along a control shaft in the inside of a fragmentation shaft. When the fragmentation shaft moves distally, the fragmentation wires pressed by a sheath are expanded to a cage shape and the thrombi are removed by rotation of the fragmentation shaft. As is U.S. Pat. No. 8,475,487, the fragmentation wires only receive the torque transmitted from the one end thereof by the control ball. Thus, the thrombi are inefficiently fragmented. Because the retrieval of the fragmented thrombi is performed by suction pores disposed proximally on the sheath, the retrieval is also inefficient. When the thrombi are organized and adhered to the vessel wall, the thrombectomy effect is little if any.
U.S. Pat. No. 8,361,095 can move the fragmented thrombi by the thrombus engagement members from the blood vessel to the inside of the sheath, but it is difficult to remove the fragmented thrombi by transferring to the outside of the thrombectomy device.